The present invention relates generally to electronic circuits, and more particularly, to power management in electronic circuits.
Electronic circuits such as microprocessors, microcontroller units (MCUs), system-on-chips (SOCs), and application specific integrated circuits (ASICs) are widely used in applications including industrial applications, automobiles, home appliances, and handheld devices and often operate in different power modes including RUN, STANDBY and POWER-ON modes. An example of a conventional electronic circuit 100 is illustrated in FIG. 1. The electronic circuit 100 includes a core power supply 102, a power management circuit 104, and digital and analog circuit domains 106 and 108. The power management circuit 104 includes a master state machine 110. The digital circuit domain 106 includes a plurality of digital circuit modules including first and second digital circuit modules 112a and 112b (collectively referred to as digital circuit modules 112) and a plurality of digital state machines including first and second digital state machines 114a and 114b (collectively referred to as digital state machines 114). Similarly, the analog circuit domain 108 includes a plurality of analog circuit modules including first and second analog circuit modules 116a and 116b (collectively referred to as analog circuit modules 116). Examples of analog circuit modules 116 include low drop-out voltage regulators, universal serial bus (USB) ports, and double data rate, random access memories (DDR-RAMs).
The power management circuit 104 is connected to the core power supply 102, and the digital and analog circuit domains 106 and 108 and provides an appropriate voltage supply there circuit domains 106, 108. Each analog circuit module 116 has a corresponding digital state machine 114 to configure the mode of operation of the analog circuit module 116. The master state machine 110 provides control signals to the digital state machines 114, based on which the digital state machines 114 generate a configuration signal to configure the mode of operation of the corresponding analog circuit modules 116.
In the RUN mode, both the digital and analog circuit domains 106 and 108 receive a predefined voltage from the core power supply 102. In the STANDBY mode, the digital circuit domain 106 receives the predefined voltage and stays in an “always ON” state, while the analog circuit domain 108 is switched off. The POWER-ON mode is common to both the digital and analog circuit domains 106 and 108, in which the power management circuit 104 provides a predetermined threshold voltage to activate (or wake up) the digital and analog circuit domains 106 and 108.
The digital state machines 114 configure the mode of operation of corresponding analog circuit modules 116 and require a constant voltage supply and are maintained in an “always ON” state. For example, the power management circuit 104 provides a constant supply of 1.2V to the digital circuit domain 106 to configure the analog circuit modules 116 throughout the various modes of operation, which increases the power consumption of the electronic circuit 100. An increase in the number of analog circuit modules 116 requires a corresponding increase in the number of digital state machines 114, which further contributes to the increased power consumption of the electronic circuit 100.
In addition, each digital state machine 114 has an undesired leakage current. As the number of digital state machines 114 increases, the leakage current of the digital circuit domain 106 increase. An increase in the power consumption and current loss results in an increase in the overall operating cost of the electronic circuit 100. Moreover, an increase in the number of digital state machines 114 increases the size of the electronic circuit 100.
It would be advantageous to have an electronic circuit that has reduced current loss and power consumption across various operating modes, reduced size, and that overcomes the above-mentioned disadvantages of conventional electronic circuits.